There are many systems in various industries which require a light beam which is fairly homogenous across the span of the beam of light. Most light sources, however, produce non-homogenous light emanating from the source. However, it is possible with the use of light filtering or correcting devices to produce homogenous light which can then be used in light transmission and other systems.
Light transmitted through a fiber, for example, generally has a Gaussian distribution of light intensity as it is emitted from the end of the fiber with higher intensity levels in the center of the fiber and decreasing levels extending toward the edges of the fiber diameter. Such a light intensity profile is less desirable than a uniform profile across the output end of the fiber for use in optical related equipment and light transmission devices.
In the past, it has been common to utilize a solid glass hexagonal rod of various designs to “homogenize” the light coming from the end of a fiber to produce a substantially uniform light output from the device. Since such glass rods are fragile (and require a coating be placed on the exterior side surfaces of the rod), such systems for homogenizing light sources are fragile and do not lend themselves for use in a rugged environment in which they might be easily damaged or broken. In addition, such glass rods are relatively heavy and fairly expensive to produce.
There are also many systems in various industries which require changing direction of a light beam. Optical fibers typically may used in some of these systems. Optical fibers are transparent thin fibers, such as long, thin strands of optically pure glass, for transmitting light. Typically, optical fibers are arranged in bundles, such as optical cables, and are used in various industries to transmit light or light signals, such as digital information, over long distances. Generally, two types of optical fibers exist: single-mode fibers and multi-mode fibers. Single-mode fibers transmit infrared laser light (wavelength=1,300 to 1,550 nanometers), whereas multi-mode fibers transmit infrared light (wavelength=850 to 1,300 nm) from light-emitting diodes (LEDs). Some optical fibers can be made from plastic. These fibers have a large core (0.04 inches or 1 mm diameter) and transmit visible red light (wavelength=650 nm) from LEDs. When using optical fibers, the optical cables need to be installed by curving the optical cables in relatively large diameters. Generally, it is not possible to bend an optical fiber, for example, at around a 90.degree. angle.
As discussed above, many applications require a homogenous light beam. Therefore, a non-homogeneous light beam coming out of an optical fiber is often sent through an optical light homogenizer to ensure beam conformity. As also discussed above, typically a hexagonal glass rod manufactured out of a piece of specialized glass, such as quartz glass, is used for this purpose. The hexagonal glass rod needs to be highly polished on both ends and needs to be coated on the outside with a highly reflective coating, which creates high manufacturing cost. Furthermore, the hexagonal glass rod is highly fragile and needs to be handled carefully, which might be difficult to realize in industrial applications. Still further, the light passing through the hexagonal glass rod may lose some of its intensity and the hexagonal glass rod cannot be adjusted to different wavelengths.
Some fiber optic applications, such as data links, require more than simple point-to point connections. Fiber optic components that can redistribute, split or combine optical signals throughout a fiber optics system may be required for these applications. One type of fiber optic components that allow for redistribution of optical signals is a fiber optic coupler. A fiber optic coupler is a device that can distribute the optical signal from one fiber among two or more fibers. A fiber optic coupler can also combine the optical signal from two or more fibers into a single fiber. Fiber optic couplers attenuate the signal resulting in a loss of intensity because the input signal is divided among the output ports. Fiber optic couplers can be either active or passive devices. The difference between active and passive couplers is that a passive coupler redistributes the optical signal without optical-to-electrical conversion. Active couplers are electronic devices that split or combine the signal electrically and use fiber optic detectors and sources for input and output. An optical splitter is a passive device that typically splits the optical power carried by a single input fiber into two output fibers. The input optical power is normally split evenly between the two output fibers. However, an optical splitter may distribute the optical power carried by input power in an uneven manner. In this case, an optical splitter may split most of the power from the input fiber to one of the output fibers and only a small amount of the power into the secondary output fiber. Usually, optical splitters have low transmission efficiency resulting in a loss of optical power due to their design.
Thus, improvements may be possible by providing a rugged device that can redirect a light beam and provide a homogenous light output without use of glass optics, such as a mirror, in tightly confined regions where normal bending of optical fibers or placement of glass optics such as a mirror is not possible.
The foregoing examples of related art and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.